* improved prime numbers implementation
* fixup! Format Python code with psf/black push
* fix type hint
* fixup! Format Python code with psf/black push
* fix doctests
* updating DIRECTORY.md
* added prime tests with negative numbers
* using for instead filter
* updating DIRECTORY.md
* Remove unused typing.List
* Remove tab indentation
* print("Sorted order is:", " ".join(a))